1. Field of the Invention
The present invention relates to a support apparatus for scaling and working on an inclined roof.
2. Description of the Prior Art
Portable staging for the purpose of building and repair on inclined roof surfaces is known in the art. Artisans require that the staging be safe, portable, convenient and simple to assemble, and useful for working on steeply inclined roofs, multiply pitched roofs, chimneys and the like. Various approaches to solve these needs have been taken, among which have included platforms with non-skid supports, platforms using ridge hook ladders laid directly on a pitched roof surface, and wheeled platforms variously secured to the roof. However, many disadvantages are associated with the prior art which leave a need to be filled by the present invention.
Various means using a ladder or ladder-like braces have been developed for support of large platforms for workers. For example, U.S. Pat. No. 2,848,282, issued on Aug. 19, 1958 to Weber describes a platform and adjustable support for use with a ladder. The support includes a pair of vertical flanged members, each having a parabolic notch in its base which allow the vertical supports to be removably perched on a rung of the ladder placed on an inclined roof. A pair of horizontal members, also notched at one end to perch on a rung, are permanently affixed to a horizontal wooden platform. When in place, each vertical member is pinned to one of the horizontal members to form a right angle, whereby a assembly which straddles two or more rungs of a ladder is formed. A first disadvantage of this invention is that, once the platform is constructed, the platform blocks the use of the underlying ladder and requires the user to scale the roof or the vertical members of the platform to reach the support platform. Moreover, the platform is very narrow and limited to the width of the rungs. Both of these elements add unnecessary limitations to the size of the structure and potential danger to its user.
United Kingdom 2,199,069 by Rackam published Jun. 29, 1988 describes a roof scaffolding which can be affixed between roof ladders having hollow rungs by means of collared bolts, washers and wing nuts inserted through the hollow rungs and secured to the scaffolding. A platform support frame with telescopic guard rails extends horizontally between the roof ladders. The scaffolding is adjustable to variously inclined roof angles by aligning holes drilled at critical points in the scaffolding and fixedly securing them by means of collared bolts, washers and wing nuts. The disadvantage of this system is that at least two roof ladders are required to support the platform support frame. Moreover, the securing bolts must be manually removed and the holes realigned to adjust the assembly to variously inclined roofs.
Danish Pat. No. 49628 issued Dec. 10, 1934 shows a platform with adjustable height legs straddling rungs of a ladder-like support placed to each of side of a chimney. The support is capable of either being hooked to a similar ladder-like support laid on the oppositely pitched roof surface or to a cross-brace affixed to the roof rafters of side of the roof on which the support rests.
U.S. Pat. No. 4,695,023 issued Sep. 22, 1987 to McCafferty describes a simple ladder-supported platform for use with small objects, the platform hinged to a pair of hooked supports for hanging from a single rung of a ladder, whereby the angle of inclination of the supports relative to the platform can be adjusted by aligning and securing registered apertures in a frame with a pin. This device does not appear to be intended for the safe support of workers over a large work area. A similar device is found in U.S. Pat. No. 4,450,935 issued May 29, 1984 to Gustavus using a crank and screw assembly to adjust the angle of inclination.
U.S. Pat. No. 5,249,397 issued Oct. 5, 1993 to Monaco describes a knockdown roof platform for small objects wherein an adjustable, tubular upright leg support having frictional pads for gripping an inclined surface is hinged by a collapsible locking bracket to the platform. The hinge secures the assembly when fully extended and closes to allow the legs to be folded against the platform for storage.
U.S. Pat. No. 3,526,296, issued on Sep. 1, 1970 to Stevens describes portable staging extending downward from the ridge of a roof, which utilizes a pair of rung-less braces with hooked, swiveling ends having non-slip pads for frictional engagement of the ridge. Individual vertical and horizontal elongated braces having bifurcated ends interlock by means of pins inserted through apertures defined by the bifurcated ends and the elongated portion of the braces. A scaffold can thus be assembled and disassembled piece by piece. However, the similarity of parts and the numerous pins needed to interlock each piece with another requires unnecessary time and a familiarity with the assembly of the structure. Multiple pieces increases the risk of loss of such pieces. Moreover, during assembly, no means of support for the user exists, requiring separate supports or ladders to be put in place for assembly.
Each invention comprising a group of wheeled platforms addresses specific problems regarding means by which the user can transport humans or materials on an inclined surface. For example, U.S. Pat. No. 4,048,924 issued Sep. 20, 1977 to Wibben describes an elongated skeletal frame to transport packets of roofing panels spanning purlins which run horizontally the length of a pitched roof. The skeletal frame is supported by a wheeled carrier which rides the purlins. U.S. Pat. No. 4,646,877 issued Mar. 3, 1987 to Whan describes a wheeled scaffold capable of carrying materials and men, having steps and wherein sets of first and second wheels ride roof purlins horizontally. U.S. Pat. No. 4,132,287 issued Jan. 2, 1979 to Parolini describes a wheeled carriage designed to support a scaffold platform and move the platform vertically along an inclined roof. The horizontal platform is variably adjustable relative to the carriage by means of a crank assembly; the mobile carriage is supported from a roof ridge by conventional support lines and lift mechanisms. However, none of these inventions address needs or problems by means related to the present invention.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.